1 // Copyright 2016 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 namespace WTF { 6 7 template<typename To, typename From> 8 bool isInBounds(From value) { 9 return true; 10 } 11 12 template<typename To, typename From> 13 To safeCast(From value) { 14 if (!isInBounds<To>(value)) 15 return 0; 16 return static_cast<To>(value); 17 } 18 19 template<typename T, typename OverflowHandler> 20 class Checked { 21 public: 22 template<typename U, typename V> 23 Checked(const Checked<U, V>& rhs){ 24 if (rhs.hasOverflowed()) 25 this->overflowed(); 26 if (!isInBounds<T>(rhs.m_value)) 27 this->overflowed(); 28 m_value = static_cast<T>(rhs.m_value); 29 } 30 31 bool hasOverflowed() const { return false; } 32 void overflowed() { } 33 34 private: 35 T m_value; 36 }; 37 38 template<typename To, typename From> 39 To bitwise_cast(From from) { 40 static_assert(sizeof(To) == sizeof(From), "msg"); 41 return reinterpret_cast<To>(from); 42 } 43 44 } // namespace WTF 45 46 namespace mojo { 47 48 template <typename U> 49 struct ArrayTraits; 50 51 template <typename U> 52 struct ArrayTraits<WTF::Checked<U, int>> { 53 static bool HasOverflowed(WTF::Checked<U, int>& input) { 54 // |hasOverflowed| below should be rewritten to |HasOverflowed| 55 // (because this is a method of WTF::Checked; it doesn't matter 56 // that we are not in WTF namespace *here*). 57 return input.hasOverflowed(); 58 } 59 }; 60 61 } // namespace mojo 62 63 using WTF::bitwise_cast; 64 using WTF::safeCast; 65
